Abstract

Baicalein, a hydrophobic flavonoid, has been used in several traditional Chinese medicines. Baicalein is contained in the roots of Scutellariae radix and the fruits of Oroxylum indicum, called “phe kaa” in Thailand. Encapsulating baicalein in oil-in-water (O/W) emulsions could overcome its insolubility in water and is expected to provide new opportunities for food applications. This work seeks to formulate and characterize O/W emulsions loaded with baicalein. We investigated the effect of high-pressure homogenization pressure on the droplet size, droplet size distribution, physical stability, and baicalein retention of these O/W emulsions. A refined soybean oil solution containing 0.05 wt% baicalein was used as the dispersed phase and an aqueous solution containing 1 wt% Tween 20 as the continuous phase. O/W emulsions with a surface-weighted mean diameter (d3,2) of about 300 nm and a span of nearly two were formulated by high-pressure homogenization at 60–150 MPa. The O/W emulsion droplets loaded with baicalein were physically stable in terms of variations in d3,2 and span during 30 days of storage in the dark at 4°C. HPLC analysis demonstrated that 77–84% of initial baicalein was retained in the fresh O/W emulsions, but that declined to 36–49% during storage.

Practical applications: O/W emulsions loaded with a functional flavonoid were produced by high-pressure homogenization at different pressures. The findings obtained from this work may be of great interest for both scientific and industrial purposes, since formulation and stability were investigated. This food microstructuring technology could assist in the development of new food systems for nutrition therapy.